Grinding noise

I have a 380-oz-in-nema-23-stepper-motor (380 oz-in NEMA 23 Stepper Motor, 1/4" Shaft | CNCRouterParts) that I use as an A axis motor. I have it slaved and reversed with the Y stepper to control the Y axis. The A axis stepper has a grinding noise as it starts and stops. It also gets hotter than the other two. I've tried adjusting in Mach3's motor control and also on the G540 controller. I also...

Grinding noise